Electric starting system for internal combustion engines



May 4, 1937. J. G. SOLA 2,078,930

ELECTRIC STARTING SYSTEM FOR INTERNAL CQMBUSTION ENGINES Filed May 2, 1936 Z j 39 g-W Fly 76 J9 JJ Patented May 4, 1937 UNITED STATES rATsNT OFFICE ELECTRIC STARTING SYSTEM FOR 17 Claims.

My invention relates to electric starting systems for internal combustion engines comprising an electric starting motor, a battery, and a generator driven by the engine for keeping the battery charged, and particularly to such systems in which the starting motor is automatically thrown into operation and is automatically connected to the engine for cranking it upon the closure of the ignition switch of the engine and is then automatically disconnected when the engine begins to run on its own power, and in which the starting motor is again automatically brought into action for another starting operation, in case the engine dies after a limited number of power strokes, or for restarting the engine in case it becomes stalled at any time during its operation and while the ignition switch still remains closed. It is the object of my invention to provide an improved form and arrangement of parts in a system of this type and comprising a starting switch and actuating mechanism therefor by reason of which an improved operation may be effected, and by which the operation of the starting switch and its actuating mechanism shall be controlled by timing means adapted to operate positively in definitely timed relation to the cooperating parts, the arrangement being such that at each successive step of the operation a substantial margin of power is employed in excess of the minimum required whereby the operation is given the desired positive character so as to avoid the necessity for adjustment of the parts to a high degree of nicety and so as to avoid the necessity for readjustment from time to time to accommodate changing weather conditions.

For preventing the clashing or stripping of the gears by a starting operation, it is highly important that both the engine and the starting motor be at rest or substantially so before the starting mechanism is put into operation. If a starting operation is attempted with the starting motor already rotating at a fairly high speed the pinion on the starting motor shaft is likely to be blocked out of mesh with the fly wheel gear of the engine so as to defeat completely the attempt to throw the parts into effective operation and so as to cause the starting motor and the pinion to rotate idly until the. condition is cured by an opening of the ignition switch. If a starting operation is attempted with either the starting motor or the engine already in rotation, a smooth movement of the pinion on the starting motor shaft into mesh with the fly wheel gear of the engine is difiicult or impossible and the parts are likely to be damaged. It is accordingly one of the objects of my invention to provide an improved arrangement of parts by which the operation of the starting mechanism shall be definitely prevented until both the starting motor and the engine are at rest or at least substantially at rest. To this end, it is one of the objects of my invention to provide an improved arrangement of this type in which the means for actuating the starting switch shall be inoperative after a starting operation until both the motor and the engine are at rest, the means for actuating the starting switch being preferably controlled by .means which in turn is itself controlled and. definitely timed by the rotation of the starting motor and the engine. For carrying out this purpose, it is one of the objects of my invention to provide an improved arrangement comprising electromagnet means for opening a control switch interposed in the circuit between the starting switch mechani m and the battery whereby the starting switch is kept open so long as said electromagnet means is kept effectively energized, and to provide means for connecting said electromagnet means effectively with both the starting motor and the generator so that, so long as either the generator continues to run with the engine or the starting motor continues to rotate by its kinetic energy after being disconnected from the battery and from the engine, said electromagnet means is kept energized so as to prevent the closing of the starting switch until such rotation has ceased.

It is one of the objects of my invention to provide an improved arrangement of this type in which the connection between the battery and the starting motor is arranged with cooperating parts in effect in the form of a Wheatstone bridge, the electromagnet means mentioned above being connected across the bridge adapted by its effective energization to cause the starting switch to open and to remain open. For efiecting this result, I have provided an auxiliary resistance means in parallel relation to the starting motor, with the bridging lead including said electromagnet means connected with the starting motor at a point between the field. and the armature of the motor and connected with the resistance at such intermediate point therealong as to insure the desired balanced condition. It is one of the objects of my invention to provide an arrangebattery thcrethrough is comparatively small for at least an instant prior to the building up of normal full speed rotation of the starting motor, in which arrangement such weal; current in said one direction shall die down ompletely as the bridge reaches its balanced condition at preferably about the time when full speed rotation of the startin motor under normal full load conditions has been established, and in which there shall be a powerful current in the opposite direc tion through said electromagnet means from the battery when the bridge is thrown widely out of balance by reason or" the greatly increased effective resistance of the armature to the flow of curren from the battery therethrough by a reactance eifect when the starting motor begins to rotate at highly increased speed as the load is taken off the starting motor due to the rotation of the engine by its own power.

It will, of course, be appreciated that while the starting motor is rotating at high speed after the engine has begun to rotate on its own power a heavy current will be sent through the electromagnet means in said connection across the bridge and through one of the arm portions of said auxiliary resistance. It is one of the objects of my invention to provide an arrangement by which a connection is almost instantly effected between said electromagnet means and the starting motor in shunted relation to said auxiliary resistance following the initial rotation of the engine on its own power whereby the electromagnet means and the motor shall be connected by a low esistance circuit so as to insure that the strength of the field in said electromagnet means shall be maintained at a maximum as the speed of rotation of the starting motor decreases after the starting motor has been automatically disconnected from the engine and from the battery, such shunt connection being efiected automatically by the influence of the greatly strengthened field in said eleotromagnet means immediately following th establishment of such field.

It is another object of my invention to improve arrangements of this type in sundry details hereinafter pointed out. The preferred means by which I have accomplished my several objects are illustrated in the accompanying drawing and are hereinafter specifically described.

, That which I believe to be new and desire to cover by Letters Patent is set forth in the claims.

In the drawing,-

Fig. l is a diagrammatic view showing my improved system as applied for starting an internal combustion engine not shown;

Fig. 2 is a diagrammatic view showing in simplified form the b idge arrangement involved the Fig. 1 connections; and

Fig. 3 is a view showing a fragmentary portion of an internal combustion engine in operative relation to the starting motor of my improved system.

Referring now to the several figures of the drawing, in which corresponding parts are indicated by the same r ference characters, 5 indicates a storage battery connected to ground at l l and connected by means of a lead i2 with the starting motor 2, with a starting switch 14 interposed in the lead between the battery and the motor, he motor being connected to ground at it. In the arran ement shown, the switch 54 is normally held open by a fiat spring 53 and is adapted to be closed by the action of a core l'l operating in a coil it connected at one end to ground at 19 and connected at its opposite end to ignition system of the car s connected with the lead 20 adjacent to the switch 21 and a push button is ement shown in parallel with c arrangement is such that when switch 23 is closed for connecti ion s stem with the battery IS the ized o as to act upon the core 57 itin switch 5 for connecting the ry as will be readily The arrangement as shown comprises further a lead 25 connected at one end to the lead I2 and connected at the opposite end to a generator 21 for charging the battery is during the operation of the engine, as is usual in arrange -rents of this ty e. The generator 2'! has the usual mechanical connection with the engine so as to be driven thereby. The generator is connected to ground at 2B, and a reverse current relay 29 or" any approved type is connected in series in the lead 25 between the battery and the generator.

The means for connecting the starting motor with the engine is to be of the well-known type comprising a pinion 3U slidably mounted on the shaft of the starting motor so as to be rotated by the motor and adapted to be brought automatically int-o mesh with the gear 3! carried by the fly wheel 32 of the engine, the arrangement being such that the pinion 39 is moved by its inertia along the worm 33 into mesh with the ear 3| against the action of the spring 34 whenever the starting motor is s t into operati n. For a smooth mov "nent of the pinion into mesh with the gear, both the gear and the pinion should be at rest, or substantially so, just prior to a starting operation.

The means employed by me for controlling the operation of the parts includes an electromagnet which in the arrangement shown comprises a. coil 35 mounted upon a core 3B. In the ar rangement shown, the core bar is connected at its lower end with an auxiliary core member 31 in the form of a U upon the arm 38 of which an armature 35 is pivotally mounted. A spring 40 is connected at one end to the armature 39 and at its opposite end to a lug it carried by the core member 3?, such spring holding the armature normally in raised position with respect to the core bar 3-3 in the position as shown in Fig. l of the drawing.

Upon the arm 42 of the core member 31, I have mounted a yoke 33 upon which bar 44 is slidably mounted, a spring 425 connected between the slide bar the yoke being adapted normally to hold the bar at the limit or" its upward movement as shown in l. The contacts El and 22, constituting a switch for opening the lead 28, are mounted upon the yoke 43 and an arm carrier by the slide bar 44, whereby the spring t5 serves normally to hold the switch 2!'2.2 closed. As shown in the drawing, the eontac and E2 are insulated from the adjacent pa Upon the upper end of the slide bar .4, I have provided an arm 41 which is provided at free end with a contact if; in position to be e ed by contac '39 mounted upon the armature eii at an ll1'tllil:;- diate point in the operative downward stroke of the armature 38 as herein tter described. The contact 49 is mounted. directly upon the armature 39, while the contact 48 is insulated from the (ill the starting motor whereby a bridge arrangement is eifected by a lead 54 connected at one end with the starting motor between the field coil 55 and the armature 56 and connected at .its opposite end with the resistance at an intermediate point therealong by which the resistance is divided into two portions, filo and Eli). By this arrangement, the two portions 5m and 5lb of the resistance comprise the two arms of the bridge at one side thereof and the field and the armature of the motor comprise the two arms of the bridge at the opposite side thereof, all as is shown to advantage diagrammatically in Fig. 2, the coil of the electromagnet being con nected in series in the lead 5 3.

As will be readily understood, when the bridge as above described is in balance-d condition, there will be no current passing through the coil 35. As will be further appreciated, the resistance values of three of the arms of the bridge are substantially fixed and unvarying, the effective resistance of the armature 53 only being subject to any substantial variation. The point of connection of the lead 54 with the resistance 5! is such, in my improved arrangement, that the bridge shall be in balanced condition when the starting motor is turning the engine over at normal cranking speed. With the starting motor operating at normal cranking speed, the resistance of the armature with respect to the establishment of a current from the battery therethrough is considerably greater than the resistance of the armature with respect to the establishment of current therethrough from the battery when the motor is at rest or is rotating at a lower speed than the normal cranking speed. It is thus apparent that when the starting switch I4 is first closed for a starting operation there is a small current through the coil 35 in one direction for energizing the electromagnet to a slight extent. Such current through the coil 35 decreases in strength, however, as the speed of the motor increases to its normal value under full load conditions. When later the engine begins to operate on its own power so as to relieve the starting motor of its load, the starting motor then begins to rotate at greatly increased speed,

serving to build up very quickly a heavy reactance eilect within the armature which. serves to out down very substantially the current from the battery passing through the armature and throwing the bridge widely out of balance. The result is that a heavy current is quickly established through the coil 35 from the battery Ill in the opposite direction from that initially established therein, serving to establish a strong magnetic field through the core parts 36 and 3? in the opposite direction from that initially established when the ignition switch is first closed. This reversal of polarity of the magnet prevents permanent magnetization of the core which might otherwise slowly develop.

In my improved arrangement as shown, the strength of the spring 48 is such that the armature 39 is held in its raised position against the pull of the electromagnet when energized by a comparatively week current in the initial direction as above described. When a current of greatly increased strength is sent through the electromagnet coil 35 in the opposite direction, however, as the engine begins to operate on its own power, the armature 39 is given a sharp downward stroke against the action of the spring 49 serving to bring the contact 49 into engagement with the contact 48 and to press the slide bar 44 downwardly against the action of the spring 45 for opening the switch 2l-22. This serves to deenergize the coil If! so as to permit the spring It to open the starting switch for disconnecting the battery In from the starting motor, this result being effected almost instantly following the initial power stroke of the engine.

For increasing the effectiveness of the coil 35 for the next following step of the operation, I have provided a lead 51 from the contact 48 carried by the armature bar 39 to the lead 54 adjacent to the connection of the lead 54 with the coil 35. By the provision of this lead 51, when the armature 39 moves downwardly, a low resistance circuit connection is established through the leads '54 and 51, the contacts 48 and 49, the armature 39, and the connections to ground at and at I5 between the electromagnet coil 35 and the armature of the motor independently of the other three arms of the bridge and independently of the battery. In the use of my improved system, just as in other starting devices of this type heretofore in use, the starting motor is automatically disconnected from the engine promptly as soon as the engine begins to operate on its own power, this result being effected through the medium of the Worm 33 in a well understood manner. As a result of my improved arrangement, as soon as the starting switch l4 opens as above described for disconnecting the motor from the battery so as to permit the motor to function as a generator, current is fed from the starting motor, rotating by kinetic energy, directly to the electromagnet through the low resistance circuit as specifled for keeping such magnet energized so as to hold the armature 39 down as long as the starting motor continues to rotate. With the armature 39 held down so as to hold the switch 2 l--22 open, the battery I9 is unable under any circumstances to cause the starting switch H to close. The starting motor is thus by positive action held out of operation as a motor for effecting a new starting operation until after the rotation of the motor has ceased.

For assuring that the starting motor shall be held out of operation also until after the rotation of the generator 21 has ceased, I have provided a second coil 58 on the core bar 38 connected at one end to the core member 31 for effective connection to ground at 50 and connected at its other end by a lead 59 to the lead 26 between the relay 23 and the generator 21'. The coil 58 is made of fairly small wire so as to limit the current loss therethrough whereby the strength of the field produced by the coil 58 is insufficient by a considerable margin for drawing the armature 39 down against the action of the spring 40. The field as produced by the energization of the coil 58 is strong enough however for holding the armature 39 down at the limit of its operative stroke after it has been moved down by the action of the coil 35 so as to insure that the switch 2 l-22 shall be kept open as long as the generator 21 rotates with the engine. When the engine is running on its own power after the starting motor has come to rest following the starting operation, the coil 58 serves by itself to hold the armature 38 continuously down so as to prevent the closing of the switch Zi-ZZ. When under these circumstances the engine for any reason ceases to operate on its own power, the strength of the field produced by the coil 58 gradually weakens as the speed of rotation of the generator decreases, but the armature is not permitted to move upwardly until the generator comes practically to a full stop.

I have described the bridge as being in balanced condition when the starting motor is turning the engine over at normal cranking speed, and I prefer this particular arrangement though it is not essential. By the use of this arrange ment, by reason of which the initial flow of current is in one direction and the later how is in the opposite direction through the coil 35, the magnetic flux through the core parts 36 and 3? is periodically re ersed. The tendency for the core to become permanently magnetized is thus combated and the mechanism is kept at all times in actively operative condition.

It is believed to be unnecessary to describe the operation of the mechanism at length in addition to the references thereto in the description of the apparatus. It will be understood that when the ignition switch 23 is closed, with the parts in the position as shown in Fig. 1, current from the battery 1 8 is delivered through the leads !2 and 20 to the coil I8 so as to draw the core I! of the switch starting mechanism toward the right in said Fig. 1 for closing the starting switch. The starting motor 13 is thus thrown into operation, serving to cause the pinion to be shifted into mesh with the gear 3! of the engine so as to crank the engine, and SEIVlllg to cause the generator 2'! also to operate at slow speed. While the starting motor i3 builds up speed in the cranking operation, a weak current flows from the battery 10 across the bridge through the electroniagnet coil 35 for establishing a flux in the 00 e, but the attraction is insuiilcient for causing the armature 39 to move downwardly against the action of the spring 36. When, however, the engine begins to operate on its own power so as to relieve the starting motor of its load and so as to throw the pinion 36 out of mesh with the engine gear 3 l, the starting motor increases very substantially in speed. This results in a very substantial increase in the resistance to the flow of current from the batter through the arrnature 56, with the result that the bridge becomes widely unbalanced and a heavy current is caused to flow through the coil 35 in the reverse di ection from that in which the current flowed initially through the coil as above described. Upon the establishment of a strong magnetic link through the core parts 36 3? of the magnet in this manner, the armature is drawn sharply downward, bringing the contacts 48 and together and serving to push the slide rod 1-5 dowrwardly for moving the contact 2i out of on ment with the contact 22. This results in the demagnetization of the coil I 8 so as to p unit the spring 8 to open the starting switch it for disconnecting the motor from the batter i the engagement of the contact to with the contact 48, the coil 35 and the motor are connected together by a low resistance circuit through which current is fed by the starting motor functioning as a generator, such current serving to energize the coil 35. At the same time, the generator 21 is feeding current to the coil 58 so as to assist the coil 35 in the maintenance of a magnetic flux through the core parts 36 and 31 for holding the armature 39 in its lowered position. The arrangement is such that the spring 40 is not able to raise the armature 39 against the attractive force of the elcctromagnet until both the generator 2? and the starting motor 13 have come to rest, or substai "ially so. When the armature moves upwardly, the switch 2i22 is again closed by the spring so to cause the starting switch 14 again to closed for a renewed operation of starting the engine. Such renewed starting operation cannot, however, be effected until both the gen tor and the motor l3 are substantially at re W nle 'i prefer to e..=i m-ent as illustrated a to be understood that thereto except so for as be so limited in tern" changes in the I he form of arrangeabove described, it is .ention is not limited rrower claims may g understood that i may well be made -o1 my invention.

' .g for an internal comme combination of a starting ted by the operation of said motor for star e engine, on electric battery, and means o nne an electromagnct energized initially by on therethrough in one motor, inea s direction r and energized much more strongly when the engine begins to o by current therethr ugh .ctr'on from said batv for 1' out or" operation and energize-cl tinned ergy aite motor until after rest.

2. In a st rting bustion en, ine, the starting note of said moto battery, means connecting the iroduced by the com- "o by its kinetic enfor preventing the n into operation for an internal comof an electric the battery for operating the mot neans compri ng an electromagnet "'ally by current therethrough irorn battery and .ly thereafter when 1 its own power by no copes from said battery for ope a l starting switch for disconnecting the met 1. 1n the battery and e ergized then by currer orcducecl by the conite direction tinned rotation of motr by its kinetic energy after starting operation for preventing the said a closure of motor has come 3. In a starting nice.

bustle-n t rest.

on internal comof an electric f i" g 1 r. an electric connecting the Cally operated and a norn ing star and means cc ergized by our closthe motor, agnet en d 70 ed switch whereby said starting sw d for disconnecting the motor iron battery and energized thereafter by current produced by the continued rotation of said motor by its kinetic energy after a starting operation for holding said normally closed switch open so as to prevent the closure of said starting switch until after the motor has come substantially to rest.

4. In a starting means for an internal cornbustion engine, the combination of an electric starting motor, actuated by the operation of said motor for starting the engine, an electric battery, means com ng a starting switch for connecting the motor with the battery, electrically operated means comprising circuit means and a normally closed switch therein for closing said starting switch for operating the motor, and means comprising an electromagnet energized initially by current therethrough in one direction from said battery and energized much more strongly thereafter when the engine begins to operate on its own power by current therethrough in the opposite direction from said battery for opening said normally closed switch so as to permit said starting switch to open for disconmeeting the motor from the battery and energized then by current produced by the continued rotation of said motor by its kinetic energy after a starting operation for holding said normally closed switch open so as to prevent the closure of said starting switch until after the motor has come substantially to rest.

5. In a starting means for an internal combustion engine, the combination of a Starting motor, means actuated by the operation of said motor for starting the engine, an electric battery, means comprising an electromagnet energized normally by a current from said battery and adapted by a considerably increased current therethrough when the engine begins to operate on its own power to throw the motor out of operation, and means serving when the motor is thrown out of operation by said electromagnet to connect said motor and said electromagnet together in a low resistance circuit independently of the battery whereby the current produced by the continued rotation of the motor by its kinetic energy keeps said electromagnet energized so long as the motor continues to rotate for preventing the motor from being again thrown into operation,

6. In a starting means for an internal combustion engine, the combination of a starting motor, means actuated by the operation of said motor for starting the engine, an electric battery, means comprising an electromagnet energized initially by current therethrough in one direction from said battery and energized much more strongly by current therethrough in the opposite direction from said battery when the engine begins to operate on its own power serving to throw the motor out of operation, and means serving when the motor is thrown out of operation by said electromagnet to connect said motor and said electromagnet together in a low resistance circuit independently of the battery whereby the current produced by the continued rotation of the motor by its kinetic energy keeps said electromagnet energized so long as the motor continues to rotate for preventing the motor from being thrown again into operation.

7. In a starting means for an internal combustion engine, the combination of an electric starting motor, means actuated by the operation of said motor for starting the engine, an electric battery, means comprising a starting switch for connecting the motor with the battery for operating the motor, means comprising an electromagnet energized initially by current therethrough in one direction from said battery and energized much more strongly by current therethrough in the opposite direction from said battery when the engine begins to operate on its own power for opening said starting switch for disconnecting the motor from the battery, and means serving when the starting switch is opened by said electromagnet to connect said motor and said electromagnet together in a low resistance circuit independently of the battery whereby the current produced by the continued rotation of the motor by its kinetic energy keeps said electromagnet energized so long as the motor continues to rotate for preventing the closure of said starting switch.

8. In a starting means for an internal combustion engine, the combination of a starting motor, means actuated by the operation of said motor for starting the engine, an electric battery, means comprising a bridge arrangement for connecting the battery and the motor together, with the field and the armature of the motor forming the two arms of the bridge at one side thereof, electromagnet means connected across the bridge, and means actuated by said electromagnet means when strongly energized for throwing said motor out of operation.

9. In a starting means for an internal combustion engine, the combination of a starting motor, means actuated by the operation of said motor for starting the engine, an electric battery, means comprising a bridge arrangement for connecting the battery and the motor together, with the field and the armature of the motor forming the two arms of the bridge at one side thereof, electromagnet means connected across the bridge, means actuated by said electromagnet means when strongly energized for throwing said motor out of operation, and means serving when said motor is thrown out of operation for connecting the armature of the motor with said electromagnet means in shunted re1ation to the remaining portions of the bridge whereby the current produced by the continued rotation of the motor by its kinetic energy keeps said electromagnet means energized so long as the motor continues to rotate for preventing the motor from being thrown again into operation. 10. In a starting means for an internal combustion engine, the combination of a starting motor, means actuated by the operation of said motor for starting the engine, an electric battery, means comprising a bridge arrangement for connecting the battery and the motor together, with the field and the armature of the motor forming the two arms of the bridge at one side thereof and with the bridge arranged so as to be in substantially balanced condition when the motor is turning the engine over at normal cranking speed, electromagnet means connected across the bridge, and means actuated by said electromagnet means for throwing the motor out of operation when the engine begins to operate on its own power so as to substantially unbalance said bridge.

11. In a starting means for an internal combustion engine, the combination of a starting motor, means actuated by the operation of said motor for starting the engine, an electric battery, means comprising a bridge arrangement for connecting the battery and the motor together, with the field and the armature of the motor forming the two arms of the bridge at one side thereof, electromagnet means connected across the bridge, means actuated by said electromagnet means for throwing the motor out of operation when the engine begins to operate on its own power and thus throwing the bridge substantially out of balanced condition by relieving the motor of its load, and means serving when said motor is thrown out of operation for connecting the armature of the motor and said electromagnet means in shunted relation to the remaining portions of the bridge whereby the current produced. by the continued rotation of the motor by its kinetic energy keeps said electromagnet means energized so long as the motor continues to rotate and thus prevents the motor from being thrown again into operation.

12. In a starting means for an internal combustion engine, the combination of a starting motor, means actuated by the ope ation of said motor for starting the engine, an electric battery, circuit means for connecting the battery and the motor together, resistance means connected. with the battery in parallel shunt relation to the motor, a lead comprising electromagnet means connected at one end with the motor at a point between the field and the armature of the motor and connected at its opposite end with the resistance means at such a point therealong as to provide a bridge arrangement which is in substantially balanced condition when the motor is turning the engine over at normal cranking speed, and means actuated by said electromagnet mes when the engine begins to operate on its 0 ,n power for throwing the motor out of operation.

13. In a starting means for an internal coinbustion engine, the combination of electri starting motor, means actuated by the operation of said motor for starting the engine, an electric battery, circuit means comprising a starting switch for connecting the motor with the battery for operating the motor, resistance means connected with the battery in parallel shunt relation to the motor, a lead comprising electromagnet means connected at one end with the motor at a point between the field and the armature of the motor and connected its opposite end with the resistance means at such point therealong as to provide a bridge arrangement whereby when said starting switch is closed there is a current through said electromagnet in one direction before the starting motor reaches its normal cranking speed and a greatly increased current through said electromagnet in the opposite direction when the starting motor is rotating at greatly increased speed after the engine has begun to operate on its own power, and means actuated by said electromagnet when the engine begins to operate on its own power for opening said starting switch for throwing the motor out of operation.

14. In a starting means for an internal cornbustion engine, the combination of an electric starting motor, means actuated by the operation of said motor for starting the engine, an electric battery, circuit means comprising a starting switch for connecting the motor with the battery for operating the motor, resistance means connected with the battery in parallel shunt relation to the motor, a lead comprising electromagnet means connected at one end with the motor at a point between the field and the armature of the motor and connected at its opposite end with the resistance means at such point there along as to provide a bridge arrangement whereby when said starting switch is closed there is a current through said electromagnet in one direction before the starting motor reaches its normal cranking speed and a greatly increased current through said electromagnet in the opposite direction when the starting motor is rotating at greatly increased speed after the engine has begun to operate on its own power, means actuated by said electromagnet when the engine begins to operate on its own power for opening said starting switch for throwing the motor out of operation, and means serving when the motor is thrown out of operation by said electromagnet to connect said motor and said electromagnet together in a low resistance circuit independently of the battery and independently of the resistance means of said bridge whereby the current produced by the continued rotation of the motor by its kinetic energy keeps said electromagnet energized so long as the motor continues to rotate for holding said starting switch open.

15. In a starting means for an internal combustion engine, the combination of a starting motor, means actuated by the operation of said motor for starting the engine, an electric battery, means comprising a bridge arrangement for connecting the battery and the motor together, with the field and the armature of the motor forming two of the arms of said bridge, electromagnet means connected across the bridge, control means actuated by said electromagnet means when strongly energized adapted by an operative stroke to throw said motor out of operation, means serving when said motor is thrown out or" operation for connecting the armature of the motor with said electromagnet means in shunted relation to the remaining portions of the bridge whereby the current produced by the continued rotation of the motor by its kinetic energy keeps said electromagnet means energized so long as the motor continues to rotate for preventing the motor from being thrown again into operation, a generator driven by the engine for charging the battery, and auxiliary electromagnet means electrically connected with said generator for energization thereby adapted when said control means has been given an operative stroke for throwing the starting motor out of operation to hold said control means against a return stroke so long as said generator continues to rotate.

16. In a starting means for an internal combustion engine, the combination of a starting motor, means actuated by the operation of said motor for starting the engine, an electric battery, a control member adapted by an operative stroke in one direction to throw said motor out of operation, an electromagnet energized initially by current therethrough in one direction from said battery and energized much more strongly by current therethrough in the opposite direction from said battery when the engine begins to operate on its own power for giving said control member an operative stroke for throwing the motor out of operation, means serving when the motor is thrown out of operation by said electromagnet to connect said motor and said electromagnet together in a low resistance circuit independently of the battery whereby the current produced by the continued rotation of the motor by its kinetic energy keeps said electromagnet energized so long as the motor continues to rotate so as to prevent the motor from being thrown again into operation, a generator driven by the engine for charging the battery, and auxiliary electromagnet means electrically connected with said generator for energlzation thereby adapted when said control means has been given an operative stroke in the direction for throwing the motor out of operation to hold said control means against a return stroke so long as said generator continues to rotate serving thus to prevent the starting motor from being thrown again into operation until said generator has come to rest.

17. In a starting means for an internal combustion engine, the combination of a starting motor, means actuated by the operation of said motor for starting the engine, an electric oattery, means comprising a starting switch for connecting the motor with the battery, means for closing said starting switch for throwing the motor out of operation, means comprising an electromagnet energized normally by a current from said battery and adapted by a considerably increased current therethrough when the engine begins to operate on its own power to open said starting switch for throwing the motor out of operation, a generator driven by the engine for charging the battery, and auxiliary electromagnet means electrically connected with said generator for energization thereby adapted when said starting switch has been opened for throwing the motor out of operation to prevent said switch from 'being again thrown into operation until said generator has come to rest.

JOSEPH G. SOLA. 

